Human tooth enamel—consisting primarily of hydroxycarbonate apatite, a crystalline calcium phosphate mineral—naturally undergoes a process of demineralization. Exposure of the enamel to saliva and food leaches minerals from teeth over time and eventually may lead to an increased susceptibility to decay, dentin hypersensitivity, incipient caries, and even carious dentin demineralization.
Bioactive glasses have demonstrated an ability to remineralize teeth and reduce dentin hypersensitivity by reacting with body fluids in the oral cavity to immediately and continuously release calcium and phosphate ions from core silica particles that then crystallize into a stable hydroxycarbonate apatite layer. This crystalline layer is deposited onto and into dentin tubules and effectively both remineralizes teeth and reduces dentin hypersensitivity immediately and in the long term.
A dentifrice composition containing bioactive glass that is suitable for routine daily use to counteract the natural demineralization process is therefore desirable. However, conventional dentifrice compositions including bioactive glass are unsuitable for regular use as for example, toothpastes, because these compositions are water-based and the calcium ions released by the bioactive glass reacts and crosslink with water molecules to form unacceptably thick pastes. The inventors have developed non-aqueous formulations that overcome the difficulty in incorporating conventional gums that provide acceptable mouth-feel and prevent component separation in toothpastes. Accordingly, the invention encompasses non-aqueous dentifrice compositions containing a bioacceptable and bioactive glass that is suitable for routine, regular use and that provides acceptable mouth-feel, foam, and product stability.